会计专业大学生就业现状及对策研究

文章分析了会计专业的大学生就业趋向、就业形势,探讨了大学生就业能力的现状及怎样提高会计类大学生就业能力.     

我国制造业升级对能源消费结构影响的实证研究——基于制造业30个行业面板数据的门槛模型分析

选取制造业30个细分行业2005—2011年的数据,从制造业结构优度和价值链高度2个维度出发,构造产业结构升级指标,建立STIRPAT模型,并在此基础上分别以企业规模和人力资本为门槛变量,建立制造业升级与能源消费结构的动态面板门槛模型,深入探究2者之间的非线性关系.研究发现:制造业升级对能源消费结构的影响程度最大,并且2者之间存在显著的双重门槛效应.当企业规模小于14.292或大于17.353时,制造业升级能够显著改善能源消费结构,而当企业规模介于14.292~17.353时,制造业升级却增加了煤炭消费量,从而恶化了能源消费结构;当以人力资本为门槛变量时所测得的门槛值分别为0.015和0.070,并且企业人力资本投入力度越大,制造业升级对改善能源消费结构存在的积极作用越明显.最后,据此提出了加大产业技术投资比例,适度扩大企业规模及提高人力资本水平的政策建议.     

Vibration research of the AC dipole-girder system for CSNS/RCS

The China Spallation Neutron Source (CSNS) is a high intensity proton accelerator based facility. Its accelerator complex includes two main parts: an H^- linac and a rapid cycling synchrotron (RCS). The RCS accumulates the 80 MeV proton beam and accelerates it to 1.6 GeV, with a repetition rate of 25 Hz. The AC dipole of the CSNS/RCS is operated at a 25 Hz sinusoidal alternating current which causes severe vibration. The vibration will influence the long-term safety and reliable operation of the magnet. The dipole magnet of CSNS/RCS is an active vibration equipment, which is different from the ground vibration accelerator. It is very important to design and study the dynamic characteristics of the dipole-girder system. This paper takes the AC dipole and girder as a specific model system. A method for studying the dynamic characteristics of the system is put forward by combining theoretical calculation with experimental testing. The ANSYS simulation method plays a very important role in the girder structure design stage. With this method, the mechanical resonance phenomenon was avoided in the girder design time. At the same time the dipole vibratory force will influence the other equipment through the girder. Since it is necessary to isolate and decrease the dipole vibration, a new isolator was designed to isolate the vibratory force and decrease the vibration amplitude of the magnet.     

Study of the dynamic characteristics of the AC dipole-girder system for CSNS/RCS

China Spallation Neutron Source (CSNS) is a high intensity proton accelerator-based facility. Its accelerator complex includes two main parts: an H- linac and a rapid cycling synchrotron (RCS). The RCS accumulates an 80 MeV proton beam and accelerates it to 1.6 GeV, with a repetition rate of 25 Hz. The AC dipole of the CSNS/RCS is operated at a 25 Hz sinusoidal alternating current which causes severe vibration. The vibration will influence the long-term safety and reliable operation of the magnet. The CSNS/RCS AC dipole-girder system takes vibration isolator to decrease the vibratory force and the vibration amplitude of the dipole. For the long-term safety and reliable operation of the dipole, it is very important to study the dynamic characteristics of the dipole-girder system. This paper takes the dipole-girder as a specific model system. A method for studying the dynamic characteristics of the system is put forward by combining theoretical calculation with experimental testing. The modal parameters with and without vibration isolator of the dipole-girder system are obtained through ANSYS simulation and testing. Then, the dynamic response of the system is calculated with modal analysis and vibration testing data. With the simulation and testing method, the dynamic characteristics of the AC dipole-girder are studied.     

乡土植物视角下秦皇岛乡村植物景观优化策略

阐述了乡土植物与乡村景观的关系,分析了乡土植物的作用,结合秦皇岛乡村植物景观现状,从观念、功能、文化、产业等角度提出了秦皇岛乡村景观的优化策略。